<?php

/**
 * EXHIBIT A. Common Public Attribution License Version 1.0
 * The contents of this file are subject to the Common Public Attribution License Version 1.0 (the “License”);
 * you may not use this file except in compliance with the License. You may obtain a copy of the License at
 * http://www.oxwall.org/license. The License is based on the Mozilla Public License Version 1.1
 * but Sections 14 and 15 have been added to cover use of software over a computer network and provide for
 * limited attribution for the Original Developer. In addition, Exhibit A has been modified to be consistent
 * with Exhibit B. Software distributed under the License is distributed on an “AS IS” basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the specific language
 * governing rights and limitations under the License. The Original Code is Oxwall software.
 * The Initial Developer of the Original Code is Oxwall Foundation (http://www.oxwall.org/foundation).
 * All portions of the code written by Oxwall Foundation are Copyright (c) 2011. All Rights Reserved.

 * EXHIBIT B. Attribution Information
 * Attribution Copyright Notice: Copyright 2011 Oxwall Foundation. All rights reserved.
 * Attribution Phrase (not exceeding 10 words): Powered by Oxwall community software
 * Attribution URL: http://www.oxwall.org/
 * Graphic Image as provided in the Covered Code.
 * Display of Attribution Information is required in Larger Works which are defined in the CPAL as a work
 * which combines Covered Code or portions thereof with code not governed by the terms of the CPAL.
 */

/**
 * Database cache service
 *
 * @author Sergey Kambalin <greyexpert@gmail.com>
 * @package ow_system_plugins.base.bol
 * @since 1.0
 */
class BOL_DbCacheService implements OW_CacheService
{
    /**
     * 
     * @var BOL_DbCacheDao
     */
    private $dbCacheDao;

    private function __construct()
    {
        $this->dbCacheDao = BOL_DbCacheDao::getInstance();
    }
    /**
     * Class instance
     *
     * @var BOL_DbCacheService
     */
    private static $classInstance;

    /**
     * Returns class instance
     *
     * @return BOL_DbCacheService
     */
    public static function getInstance()
    {
        if ( !isset(self::$classInstance) )
        {
            self::$classInstance = new self();
        }

        return self::$classInstance;
    }

    public function get( $key )
    {
        $dto = $this->dbCacheDao->findByName($key);

        return $dto === null ? false : $dto->value;
    }

    public function set( $key, $var, $lifeTime = 0 )
    {
        $dto = $this->dbCacheDao->findByName($key);

        if ( $dto === null )
        {
            $dto = new BOL_DbCache();
            $dto->name = $key;
        }

        $dto->expireStamp = empty($lifeTime) ? PHP_INT_MAX : time() + $lifeTime;
        $dto->value = $var;

        $this->dbCacheDao->save($dto);
    }

    public function deleteExpiredList()
    {
        $this->dbCacheDao->deleteExpiredList();
    }
}